Chemical irritants

Chronic pulp inflammation under deep fillings was long held to be caused by toxic components leaking from the filling material and diffusing to the pulp via dentinal tubules. However, research has shown that the reason for pulp irritation is microbial leakage, not the material itself. If bacterial leakage is inhibited by a zinc oxide eugenol topfilling (illustration in the main window), no pulpal inflammation occurs.

More recent studies have also shown that dentine is an effective buffer against acidic (from dentine etching) and alkaline substances. However, direct application of caustic or toxic chemicals on the pulp will cause inflammatory reaction and local or even total pulp necrosis.